Yes, liquidators can be replaced. If creditors want to replace a liquidator, they need to vote out the incumbent at an official creditors meeting. However, they need to have a replacement lined up; and this replacement must have provided a written guarantee that they will accept the job.
Courts can also order that a liquidator be replaced. This would happen only if a creditor or someone else with a financial interest in the liquidation had filed an application with the court.
Directors can’t order the replacement of a liquidator, even if it was them who chose the liquidator.